1. Field of the Invention
The present invention generally relates to recognition methods of prohibited articles, explosives or drugs in computed tomogram imaging data, and more particularly, to recognition methods of flaky or blocky prohibited articles, explosives or drugs.
2. Description of the Related Art
Since 9-11 event of the United States, security inspection in aviation industry has become more and more concerned. CT technique based security inspection products have incomparable advancement, and significant property superiority. TSA mechanism of US contends that one important way for achieving safety inspection in airports is to employ CT apparatuses and inspection methods thereof. The recognition to the flaky or blocky prohibited articles is one key technique for the CT apparatus, which play a pivotal role to inspect the prohibited articles hidden in the luggage and parcel. Particularly, the recognition method of the flaky prohibited articles would prevent the prohibited articles being entrained in books or notebooks.
Through analysis of several references U.S. Pat. No. 6,195,444 B1, CN 1305610A and CN 1178019A in the prior art, it can be apparent that they all employ methods of directly analyzing three-dimensional volume data, and thus the three-dimensional data will not be analyzed till the last tomogram data is obtained. Therefore, this results in a period of waiting time. In this way, this causes the following disadvantages: too much waiting and analyzing time, and relatively long time delay, due to too many tomogram data to be analyzed, huge amount of data is, and long time for analyzing after the last tomogram data are acquired. In the above patent references, a cube background method or morphological erosion method is used to inspect the flaky objects. This indirectly utilizes physical features that the flaky objects have a relatively thin thickness, and it is not convenient to set parameters thereof. The cube background method has high complexity and large computing amount. And further, when the flaky object is close to one blocky object, or has many pixels adjacent thereto, this method tends to become invalid and neglect some objects upon recognizing, since the pixels to be detected have little differences from the background pixels.
In view of this, there indeed needs to provide recognition methods of flaky or blocky prohibited articles, explosives or drugs, which can reduce or eliminate the time delay.